ASE Brakes T4
Practice Test #2
with complete
verified
solutions
Technician A says the same electronic control unit (ECU) operates the
antilock braking systems (ABSs) on the tractor and the trailer. Technician
B says that if replacement tires are of different size from the original tires,
the wheel speed sensor signals are affected. Who is correct?
A. A only
B. B only
C. Both A and B
D. Neither A nor B
Answer A is incorrect. The tractor and trailer ABSs have separate ECUs.
Answer B is correct. Only Technician B is correct. If replacement tires are a
different size compared to the original tires, the wheel speed sensor
signals are affected.
Answer C is incorrect. Technician A is incorrect.
Answer D is incorrect. Technician B is correct.
A truck with air brakes and a suspended (firewall-mounted) pedal has a
low pedal. Which of the following could be the cause?
A. The brakes are adjusted too tight.
B. No air pressure in the primary brake circuit.
C. The brake pedal pushrod is too long.
D. The parking brake is broken.
,Answer A is incorrect. If the brakes are adjusted too tight they will drag,
which will not cause a low pedal. It will cause hot brakes.
Answer B is correct. When there is a failure in the primary brake circuit,
the primary piston will mechanically travel in the bore and push the
secondary piston to operate the secondary brakes. This will cause the
driver to feel the pedal traveling farther than normal, thus resulting in a
low pedal.
Answer C is incorrect. A pushrod that is too long would cause the brakes
to drag.
Answer D is incorrect. The parking brake spring applies the parking brake.
If the spring is broken, the parking brake may fail to hold the truck parked
on a hill.
Referring to the figure above, there is an air leak from the service relay
when the parking brakes are released using the dash-mounted valve.
Technician A says the service relay may be faulty. Technician B says the
parking brake chamber may be faulty. Who is correct?
A. A only
B. Bonly
C. Both A and B
D. Neither A nor B
Answer A is incorrect. The service relay should not have air applied to it
during this operation. The service relay is not faulty.
Answer B is correct. The parking brake chamber is allowing air through the
center seal and it is flowing back into the service relay valve. The open
exhaust of the service relay valve is allowing the air to escape. The
parking brake chamber will need to be replaced.
Answer C is incorrect. Technician A is incorrect.
Answer D is incorrect. Technician B is correct.
A truck with hydraulic disc brakes has dragging brakes. Technician A says
the calipers may be sticking. Technician B says the master cylinder may be
passing fluid. Who is correct?
A. A only
B. B only
C. Both A and B
D. Neither A nor B
Answer A is correct. Sticking caliper shides can cause the brakes to drag.
Answer B is incorrect. A by passing master cylinder will cause the brake
pedal to be low.
Answer C is incorrect. Technician B is incorrect.
Answer D is incorrect. Technician A is correct.
Which of the following could cause one brake on a truck to wear faster
than the others?
A. A restricted service brake hose
В. A restricted air line between the supply and primary tank
, C. Low air pressure in the service tanks D. Governor cut-out pressure too
high
Answer A is correct. A restricted service brake hose would allow unequal
brake applications and thus unequal brake wear. Also, the air would not be
able to release from the brake chamber, causing that brake to drag.
Answer B is incorrect. A restricted line berween the supply and primary
reservoir would affect the entire primary braking circuit, not just one
brake.
Answer C is incorrect. Low air pressure in the tanks would not cause brake
wear. It may cause a low amount of reserve air in case of multiple brake
applications.
Answer D is incorrect. High governor cut-out pressure may cause the
safery valve to open but would not cause the brakes to wear too quickly.
The front brakes on a truck are being checked. The drum rolls freely
backward but hangs and stops when rotated forward by hand. Technician
A says the problem could be a broken slack adjuster. Technician B says the
problem could be an incorrectly adjusted hand brake valve. Who is
correct?
A. A only
B. B only
C. Both A and B
D. Neither A nor B
Answer A is incorrect. Technician A is incorrect. A broken slack will prevent
proper application. In the unakely event that it happened to cause the
brake to drag, the brake would drag equally in both directions.
Answer B is incorrect. Technician B is incomet. The hand brake operates
the trailer brakes, not the steer axle brakes.
Answer C is incorrect. Both Technicians are incorrect.
Answer D is correct. Both Technicians are incorrect. This indicates a
broken return spring.
On a tractor with air brakes, the parking brake on the tractor will not
release, but the trailer brakes work correctly. Which of the following is the
most likely cause?
A. Shorted brake light switch
B. Stuck parking brake relay valve
C. Stuck service brake relay valve
D. A hand valve slightly stuck on
Answer A is incorrect. A shorted brake light switch would allow the lights
to operate all the time. It would not affect parking brake operation.
Answer B is correct. A stuck tractor parking brake relay valve could
prevent air from entering the spring brake chamber and prevent the
parking brake from releasing.
Answer C is incorrect. The service brake relay valve could prevent the
service brakes from working, but would not prevent the parking brakes
Practice Test #2
with complete
verified
solutions
Technician A says the same electronic control unit (ECU) operates the
antilock braking systems (ABSs) on the tractor and the trailer. Technician
B says that if replacement tires are of different size from the original tires,
the wheel speed sensor signals are affected. Who is correct?
A. A only
B. B only
C. Both A and B
D. Neither A nor B
Answer A is incorrect. The tractor and trailer ABSs have separate ECUs.
Answer B is correct. Only Technician B is correct. If replacement tires are a
different size compared to the original tires, the wheel speed sensor
signals are affected.
Answer C is incorrect. Technician A is incorrect.
Answer D is incorrect. Technician B is correct.
A truck with air brakes and a suspended (firewall-mounted) pedal has a
low pedal. Which of the following could be the cause?
A. The brakes are adjusted too tight.
B. No air pressure in the primary brake circuit.
C. The brake pedal pushrod is too long.
D. The parking brake is broken.
,Answer A is incorrect. If the brakes are adjusted too tight they will drag,
which will not cause a low pedal. It will cause hot brakes.
Answer B is correct. When there is a failure in the primary brake circuit,
the primary piston will mechanically travel in the bore and push the
secondary piston to operate the secondary brakes. This will cause the
driver to feel the pedal traveling farther than normal, thus resulting in a
low pedal.
Answer C is incorrect. A pushrod that is too long would cause the brakes
to drag.
Answer D is incorrect. The parking brake spring applies the parking brake.
If the spring is broken, the parking brake may fail to hold the truck parked
on a hill.
Referring to the figure above, there is an air leak from the service relay
when the parking brakes are released using the dash-mounted valve.
Technician A says the service relay may be faulty. Technician B says the
parking brake chamber may be faulty. Who is correct?
A. A only
B. Bonly
C. Both A and B
D. Neither A nor B
Answer A is incorrect. The service relay should not have air applied to it
during this operation. The service relay is not faulty.
Answer B is correct. The parking brake chamber is allowing air through the
center seal and it is flowing back into the service relay valve. The open
exhaust of the service relay valve is allowing the air to escape. The
parking brake chamber will need to be replaced.
Answer C is incorrect. Technician A is incorrect.
Answer D is incorrect. Technician B is correct.
A truck with hydraulic disc brakes has dragging brakes. Technician A says
the calipers may be sticking. Technician B says the master cylinder may be
passing fluid. Who is correct?
A. A only
B. B only
C. Both A and B
D. Neither A nor B
Answer A is correct. Sticking caliper shides can cause the brakes to drag.
Answer B is incorrect. A by passing master cylinder will cause the brake
pedal to be low.
Answer C is incorrect. Technician B is incorrect.
Answer D is incorrect. Technician A is correct.
Which of the following could cause one brake on a truck to wear faster
than the others?
A. A restricted service brake hose
В. A restricted air line between the supply and primary tank
, C. Low air pressure in the service tanks D. Governor cut-out pressure too
high
Answer A is correct. A restricted service brake hose would allow unequal
brake applications and thus unequal brake wear. Also, the air would not be
able to release from the brake chamber, causing that brake to drag.
Answer B is incorrect. A restricted line berween the supply and primary
reservoir would affect the entire primary braking circuit, not just one
brake.
Answer C is incorrect. Low air pressure in the tanks would not cause brake
wear. It may cause a low amount of reserve air in case of multiple brake
applications.
Answer D is incorrect. High governor cut-out pressure may cause the
safery valve to open but would not cause the brakes to wear too quickly.
The front brakes on a truck are being checked. The drum rolls freely
backward but hangs and stops when rotated forward by hand. Technician
A says the problem could be a broken slack adjuster. Technician B says the
problem could be an incorrectly adjusted hand brake valve. Who is
correct?
A. A only
B. B only
C. Both A and B
D. Neither A nor B
Answer A is incorrect. Technician A is incorrect. A broken slack will prevent
proper application. In the unakely event that it happened to cause the
brake to drag, the brake would drag equally in both directions.
Answer B is incorrect. Technician B is incomet. The hand brake operates
the trailer brakes, not the steer axle brakes.
Answer C is incorrect. Both Technicians are incorrect.
Answer D is correct. Both Technicians are incorrect. This indicates a
broken return spring.
On a tractor with air brakes, the parking brake on the tractor will not
release, but the trailer brakes work correctly. Which of the following is the
most likely cause?
A. Shorted brake light switch
B. Stuck parking brake relay valve
C. Stuck service brake relay valve
D. A hand valve slightly stuck on
Answer A is incorrect. A shorted brake light switch would allow the lights
to operate all the time. It would not affect parking brake operation.
Answer B is correct. A stuck tractor parking brake relay valve could
prevent air from entering the spring brake chamber and prevent the
parking brake from releasing.
Answer C is incorrect. The service brake relay valve could prevent the
service brakes from working, but would not prevent the parking brakes
